Bearing device, conveying device, inspection device, and machine tool

Abstract

A bearing includes an inner ring and an outer ring arranged to face each other with a rolling element interposed therebetween, and a housing including a housing inner supported by the inner ring and a rotor flange supported by the outer ring. The rotor flange includes a flange portion extending toward one end surface side in an axial direction of the outer ring, and a C-type retaining ring arranged at the other end surface side in the axial direction of the outer ring. A push ring formed of a resin material is provided in a gap between the flange portion and the one end surface in the axial direction.

The invention claimed is: 
     
       1. A direct drive motor comprising:
 a bearing including an inner ring and an outer ring arranged to face each other in a relatively rotatable manner, and a plurality of rolling elements interposed between the inner ring and the outer ring in a rollable manner; 
 a motor unit including a stator and a rotor rotatable with respect to the stator; and 
 a housing including: a first housing supported by the inner ring and to which the stator is fixed; and a second housing supported by the outer ring and to which the rotor is fixed, wherein 
 the inner ring is sandwiched by the first housing and an inner ring holder connected to the first housing, 
 the second housing includes: a flange portion protruding in a radial direction from an inner peripheral surface of the second housing and extending toward one end surface side in an axial direction of the outer ring; and a retaining ring arranged at the other end surface side in the axial direction of the outer ring, the flange portion and the retaining ring sandwiching the outer ring therebetween, 
 a push ring formed of a polymeric resin material that is a thermoplastic resin or a thermosetting resin is provided in a gap between the flange portion and the one end surface in the axial direction of the outer ring, or a gap between the retaining ring and the other end surface in the axial direction of the outer ring, absorbs width dimensional tolerance of the bearing and the retaining ring in the axial direction, and prevents the bearing from moving in the axial direction relative to the second housing, 
 the second housing in which the flange portion is formed includes a groove portion extending in a circumferential direction, and the retaining ring is mounted in the groove portion, 
 the push ring is provided in the gap between the flange portion and the one end surface in the axial direction of the outer ring, and 
 a first gap sealing member formed of a resin material is arranged in at least one of the gap between the retaining ring and the other end surface in the axial direction of the outer ring, and a gap between the retaining ring and the groove portion. 
 
     
     
       2. The direct drive motor according to  claim 1 , wherein the first housing and the second housing are each formed into a cylindrical shape, and the second housing in which the flange portion is formed is seamlessly molded in an extending direction of the cylinder. 
     
     
       3. The direct drive motor according to  claim 1 , wherein the push ring includes a first contact surface being in contact with the flange portion or the retaining ring, and a second contact surface being in contact with the one end surface or the other end surface in the axial direction of the outer ring,
 the first contact surface and the second contact surface are formed at positions shifted in a radial direction of the push ring, 
 the push ring includes a portion that is provided below the first contact surface in the axial direction, is continuous to the second contact surface, and is inclined in a direction away from the one end surface or the other end surface in the axial direction of the outer ring. 
 
     
     
       4. The direct drive motor according to  claim 1 , wherein the first gap sealing member is a resin film sticking on the retaining ring. 
     
     
       5. The direct drive motor according to  claim 1 , wherein the first gap sealing member is an adhesive including a main agent, and a curing agent that is mixed with the main agent and cures the main agent. 
     
     
       6. The direct drive motor according to  claim 5 , wherein the retaining ring is mounted in the groove portion in a state where one of the main agent and the curing agent is applied on the other end surface in the axial direction of the outer ring and the groove portion, and the other of the main agent and the curing agent is applied on the retaining ring. 
     
     
       7. The direct drive motor according to  claim 5 , wherein the adhesive is configured such that the curing agent encapsulated in a microcapsule is mixed in the main agent, and the curing agent and the main agent are mixed and cured by the microcapsule being broken by external force. 
     
     
       8. The direct drive motor according to  claim 1 , wherein a second gap sealing member is arranged in at least one of a gap between the inner ring and the first housing and a gap between the outer ring and the second housing. 
     
     
       9. The direct drive motor according to  claim 8 , wherein the second gap sealing member is an adhesive that is cured after being filled in the gap. 
     
     
       10. The direct drive motor according to  claim 8 , wherein the first housing and the second housing are formed of a magnetic body, and an electroless nickel-phosphorus plating process is performed on surfaces of the first housing and the second housing in which the second gap sealing member is arranged. 
     
     
       11. The direct drive motor according to  claim 1 , comprising:
 a rotation detector configured to detect a rotational state of the motor unit, wherein 
 the rotation detector is a single resolver of an incremental type that detects relative displacement of the rotor with respect to the stator. 
 
     
     
       12. The direct drive motor according to  claim 11 , wherein
 the resolver includes a resolver stator fixed to the first housing, and a resolver rotor facing the resolver stator with a predetermined interval and fixed to the second housing, and 
 the resolver rotor is fixed to the second housing to have a space on a surface at an opposite side to a facing surface facing the resolver stator. 
 
     
     
       13. The direct drive motor according to  claim 11 , comprising:
 a power factor detection unit configured to detect a position where a power factor becomes 0 when power is supplied to the motor unit; and 
 a translocation control unit configured to control translocation of the motor unit according to the position where the power factor becomes 0, and incremental information output from the resolver. 
 
     
     
       14. The direct drive motor according to  claim 11 , wherein the motor unit, the bearing, and the resolver are arranged side by side in an axial direction of the bearing. 
     
     
       15. A conveying device comprising:
 the direct drive motor according to  claim 1 , 
 wherein the conveying device is configured to convey an object to be conveyed by rotation of the first housing or the second housing. 
 
     
     
       16. An inspection device comprising:
 the direct drive motor according to  claim 1 ; and 
 an inspection unit configured to individually inspect an object moved by rotation of the first housing or the second housing. 
 
     
     
       17. A machine tool comprising:
 the direct drive motor according to  claim 1 ; and 
 a machining unit configured to individually machine an object moved by rotation of the first housing or the second housing.